Multi-analyte sensing tissue-integrating sensors

ABSTRACT

Some embodiments described herein relate to a sensor that includes a first a first polymer-luminescent sensing compound configured to produce a first luminescent signal in the presence of a first analyte and a second polymer-luminescent sensing compound configured to produce a second luminescent signal in the presence of a second analyte. The second luminescent signal can have a luminescent lifetime that is at least 1.1 times greater than a luminescent lifetime of the first luminescent signal. Such temporally differences in signal can be used to deconvolute the first luminescent signal from the second luminescent signal even when, for example, the first luminescent signal and the second luminescent signal have the same or a similar emission spectrum.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/526,961, filed on Jun. 29, 2017, the disclosures of each of which ishereby incorporated by reference in its entirety. This application isrelated to U.S. Patent Pub. No. 20120265034, entitled“Tissue-integrating sensors,” published on Oct. 18, 2012; and U.S. Pat.No. 9,375,494, entitled “Oxygen sensors,” issued on Jun. 28, 2016; theentire disclosures of which are incorporated herein by reference.

TECHNICAL FIELD

The presently disclosed subject matter relates generally to sensors formonitoring analyte levels in the body of a human or animal patientand/or subject. Sensors described herein generally include one or morepolymers and one or more luminescent sensing compounds configured toemit a luminescent signal that is dependent on a concentration and/orquantity of an analyte. Some embodiments described herein includesensors and methods for detecting multiple analytes.

BACKGROUND

Currently, sensors exist that can be implanted and integrate into thetissue of human or animal patients and/or subjects. For example, sensorsexist that can be implanted a few millimeters under the skin. Forexample, U.S. Patent Application Pub. No. 2012/0265034, entitled“Tissue-integrating sensors,” published on Oct. 18, 2012 and U.S. Pat.No. 9,375,494, entitled “Oxygen sensors,” issued on Jun. 28, 2016, theentire disclosures of which are incorporated herein by reference,describe various implantable tissue-integrating sensors. Typically, insuch sensors, luminescent sensing compounds are used to measure theconcentration of an analyte of interest (e.g., oxygen (O₂), glucose,lactate, or pyruvate). In addition to luminescent sensing compounds andother components, implantable sensors can include polymers or polymerichydrogels.

A need exists for implantable sensors capable of detecting more than oneanalyte. It is difficult or impossible to detect more than one analyteusing existing sensors. A particular challenge exists in deconvolutingsignals associated with the different analytes detected by a sensor.Additionally, a polymer scaffold suitable for one luminescent sensingcompound may not be suitable for a luminescent sensing compoundconfigured to detect another analyte. Embodiments described hereinrelate to combinations of luminescent sensing compounds and polymerssparticularly well suited to improve luminescent sensing compoundperformance and/or suitable for use as part of a multi-analyte sensingsensor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a chart illustrating a luminescent glucose sensitive compoundhaving variable luminescent intensity depending on polymer matrix,according to an embodiment.

FIG. 2, a chart illustrating an example of the choice of polymer'seffect the modulation of a luminescent sensing compound.

FIG. 3 illustrates an example of the choice of polymer's effect onintensity and lifetime of a luminescent sensing compound.

FIG. 4 illustrates a multi analyte system, including an oxygen sensitiveluminescent compound and a glucose sensitive luminescent compound.

FIG. 5 is a block diagram of a system operable to detectanalyte-dependent signals from a sensor, according to an embodiment.

FIG. 6 is a plot of an example of the emission intensity of amulti-analyte sensor.

FIGS. 7A and 7B are plots of example the emission intensities of amulti-analyte sensor.

FIG. 8, a flow diagram of method of detecting one or more analytes,according to an embodiment.

FIG. 9 is a plot of an example of the effect of different sensorcrosslinker components have on the detection sensitivity of a sensor.

DETAILED DESCRIPTION

Some embodiments described herein relate to a sensor and an analytedetection system for detecting multiple analytes simultaneously. Forexample, an analyte detection system can include a multi-analyte sensorthat includes polymers and luminescent sensing compounds. Themulti-analyte sensor may be implanted in tissue (e.g., a few millimetersunder the skin) of a human or animal patient and/or subject. An opticaldetector (or reader) that can be placed on the surface of the skin canbe operable to detect signals emitted by the multi-analyte sensor. Themulti-analyte detection system can further include processing capability(e.g., a computing entity) for processing any information from theoptical detector.

Some embodiments described herein relate to combinations (orformulations) typically containing at least a polymer (e.g., a hydrogel)and a luminescent sensing compound (also referred to herein as a “dye”).For ease of description, a formulation containing a luminescent sensingcompound and at least one polymer may be referred to herein as adye-polymer composition or a polymer-luminescent sensing compound. Theluminescent sensing compound is typically configured to emit a signalthat can be correlated to a quantity or concentration of an analyte. Insome instances, the luminescent sensing compound can be excited by afirst optical signal and emit a second optical signal (e.g., viaphosphorescence or fluorescence) that is dependent upon a quantity orconcentration of the analyte. The polymer can make up or be a componentof a tissue-integrating scaffold, which can contain the luminescentsensing compound, ensure that the luminescent sensing compound ismaintained in close proximity to biological fluids containing theanalyte, and/or form a biologically compatible structure that fixes theluminescent sensing compound in the subject's body (e.g.,subcutaneously).

Formulating various dye-polymer compositions produces unpredictableresults. Similarly stated, certain combinations of polymer andluminescent sensing compound produce synergistic results that are notapparent from an a priori examination of the individual components. Forexample, the luminescent output and/or lifetime of certain luminescentsensing compounds can vary significantly when formulated with differentpolymers. As used herein, a lifetime of a luminescent sensing compoundis the time required for an intensity of the luminescent compound todecay by a factor of 1/e (approximately 36.8%) from a peak intensity.

In addition, different dye-polymer formulations can cause a temporalcomponent of the luminescent sensing compound's characteristic emissionsto be altered. By carefully selecting polymer-dye combinations theemission duration of a luminescent sensing compound can be “tuned” to bemore easily detected by an instrument (or “reader”) configured to detectthe luminescent sensing compound. Altering the emission duration ofluminescent sensing compounds through appropriate formulation canfurther improve the ability to deconvolute signals associated withmultiple analyte sensing luminescent sensing compounds.

Some embodiments described herein relate to a sensor that includes afirst polymer-luminescent sensing compound configured to produce a firstluminescent signal in the presence of a first analyte and a secondpolymer-luminescent sensing compound configured to produce a secondluminescent signal in the presence of a second analyte. The secondluminescent signal can have a luminescent lifetime that is at least 1.1times greater than a luminescent lifetime of the first luminescentsignal. Such temporal differences in signal can be used to deconvolutethe first luminescent signal from the second luminescent signal evenwhen, for example, the first luminescent signal and the secondluminescent signal have the same or a similar emission spectrum.

Some embodiments described herein relate to a sensor that includes afirst polymer-luminescent sensing compound configured to produce a firstluminescent signal in the presence of a first analyte and a secondpolymer-luminescent sensing compound configured to produce a secondluminescent signal in the presence of a second analyte. The secondpolymer-luminescent sensing compound can include a luminescent sensingcompound and a polymer that is configured to alter a characteristic ofthe luminescent sensing compound such that the second luminescent signalis distinguishable from the first luminescent signal. The polymer canalter the lifetime and/or the intensity of the luminescent sensingcompound, for example, to provide temporally different luminescentcharacteristics and/or to cause the first luminescent signal and thesecond luminescent signals to have more similar intensities, which mayprevent one luminescent signal from “washing out” the other.

Some embodiments described herein relate to a method that can includeilluminating a sensor having a first polymer-luminescent sensingcompound and a second polymer luminescent sensing compound with anexcitation light. In response to illuminating the sensor, a luminescentsignal including a component from the first polymer-luminescent sensingcompound and a component from the second polymer luminescent sensingcompound can be received. The component from the firstpolymer-luminescent sensing compound and the component from the secondpolymer luminescent sensing compound can be deconvolved based on thefirst polymer-luminescent sensing compound having a luminescent lifetimethat is greater than a luminescent lifetime of the secondpolymer-luminescent sensing compound. A concentration of the firstanalyte can be determined based on the component of the emissionspectrum associated with first polymer-luminescent sensing compound, anda concentration of the second analyte can be determined based on thecomponent of the emission spectrum associated with secondpolymer-luminescent sensing compound.

Some embodiments herein relate to a sensor that includes a singleluminescent compound configured to emit a luminescent signal that can becorrelated to multiple analytes. In some such embodiments, a firstportion of the sensor configured to sense a first analyte can include adye-polymer formulation having a long lifetime and a second portion ofthe sensor configured to sense a second analyte can include adye-polymer formulation having a short lifetime. Thus, luminescentsignals emitted from the first portion of the sensor and the secondportion of the sensor can have different temporal signatures which canbe deconvoluted by a reader. As used herein, terms such as “longlifetime” and “short lifetime” generally refer to a relative differencebetween dye-polymer formulations and do not necessarily implyinformation about an absolute lifetime of a dye-polymer formulation. Insome instances, it may be desirable for a long lifetime dye-polymerformulation to have a lifetime that is 110%, 125%, 150%, 160% or greaterthan a lifetime of a short lifetime-dye polymer. Similarly stated, inembodiments in which a long-lifetime dye-polymer formulation has alifetime that is at least 110%, 125%, 150%, 160% or greater than alifetime of a short lifetime dye-polymer formulation, a luminescentsignal from the long lifetime dye can be readily deconvoluted from aluminescent signal from the short lifetime dye based on differences intheir respective temporal signatures.

The presently disclosed subject matter may be embodied in many differentforms and should not be construed as limited to the embodiments setforth herein; rather, these embodiments are provided so that thisdisclosure will satisfy applicable legal requirements. Indeed, manymodifications and other embodiments of the presently disclosed subjectmatter set forth herein will come to mind to one skilled in the art towhich the presently disclosed subject matter pertains having the benefitof the teachings presented in the foregoing descriptions and theassociated Drawings. Therefore, it is to be understood that thepresently disclosed subject matter is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.

Sensors that have the Ability to Detect More than One Analyte

Some embodiments described herein relate to sensors that have theability to detect more than one analyte. Such sensors can include apolymer scaffold made up of one or more polymers and one or moreluminescent sensing compounds (e.g., dyes) paired with a synergisticpolymer or polymers. The sensors can contain multiple luminescentsensing compounds each formulated differently with one or more polymers.

In an embodiment, the polymer of the scaffold may be the same as thepolymer of the first luminescent sensing compound. Similarly stated, thescaffold may be a polymerized luminescent sensing compound. In anembodiment, the polymer of the scaffold may be the different from thepolymer of the first luminescent sensing compound. In an embodiment, thepolymer of the scaffold may be the same as the polymer of the secondluminescent sensing compound. In an embodiment, the polymer of thescaffold may be the different from the polymer of the second luminescentsensing compound. The one or more luminescent sensing compounds may bechemically (e.g., covalently or non-covalently) bound to polymers of thepolymer. In an embodiment, the one or more luminescent sensing compoundsmay be physically bound to or embedded in the polymer. In someembodiments different portions of the polymer scaffold may includedifferent dye-polymer formulations.

Polymer Scaffold

In an embodiment, the polymer scaffold may include 2-hydroxyethylmethacrylate (HEMA), poly (hydroxyethyl methacrylate) (pHEMA),polyacrylamide, N-vinylpyrrolidone, N,N-Dimethylacrylamide,poly(ethylene glycol) monomethacrylate (of varying molecular weights),diethylene glycol methacrylate, N-(2-hydroxypropyl)methacrylamide,glycerol monomethacrylate, 2,3-dihydroxypropyl methacrylate andcombinations thereof.

In an embodiment, the polymer scaffold may be formed by polymerizationfrom a polymer pre-polymer solution. In an aspect, the polymerpre-polymer solution may include monomers and crosslinkers. In anaspect, the polymer pre-polymer solution may also include comonomers. Inan aspect, the pre-polymer solution may also include a polymer dispersedin the solution.

Non-limiting examples of monomers and comonomers include 2-fluoroethlymethacrylate; 3-chloro-2-hydroxypropylmethacrylate;acryloyloxyethyltrimethyl ammonium; dimethacrylamide;2-hydroxyethylmethacrylate; 2,2,3,4,4,4-hexafluorobutyl methacrylate;1,1,1,3,3,3-hexafluoroisopropyl acrylate; 1H,1H-heptafluoro-n-butylmethacrylate; methyl methacrylate; 2-methacryloyloxyethylphosphorylcholine; O-nitrobenzyl methacrylate; pentafluorobenzylmethacrylate; 1H,1H-perfluorooctyl methacrylate;[2-(methacryloyloxy)ethyl]dimethyl-(3-3sulfopropyl)ammonium;3-sulfopropyl methacrylate; 2,2,2-trifluoroethyl methacrylate;2,2,3,3-tetrafluoropropyl methacrylate; acrylamide; butylmethacrylamide;butylmethacrylate; carboxyethyl acrylate; hexyl methacrylate;hydroxypropyl methacrylate; n-hexylacrylate; [2-(methacryloyloxy)ethyl]trimethylammonium; lauryl methacrylate; benzyl methacrylate;2-(tert-butylamino) ethyl methacrylate; 2-(methacryloxy)ethyl phosphate;2-aminoethyl methacrylate; 2-bromoethyl methacrylate; trichloroethylmethacrylate; polyethylene glycol (PEG); napthylvinylpyridine (NVP); andmethacrylic acid (MAA); tetraethylene glycol dimethacrylate;poly(ethylene glycol) (n) diacrylate (of varying molecular weights);ethoxylated trimethylolpropane triacrylate; and bisacrylamide

Non-limiting examples of crosslinkers include bisacrylamide; bisphenol Aglycerolate diacrylate; tricycle decanedimethanol diacrylate;di(trimethylolpropane) tetra-acrylate; ethylene glycol dimethacrylate;ethylene bisacrylamide; 1,6-hexanediol diacrylate; neopentyl glycoldiacrylate; 2,2,3,3,4,4,5,5-octafluoro-1,6-hexyl dimethacrylate;pentaerythritol triacrylate; pentaerythritol tetraacrylate;poly(ethylene glycol) diacrylate; poly(ethylene glycol) diacrylamide;tetraethylene glycol dimethacrylate; trimethylolpropane tri-acrylate;and diurethane dimethacrylate.

In one example, a polymer matrix comprising a compound with afluorocarbon benzyl ring with the following structure can be used toincrease the lifetime of a porphyrin dye to about 410 μs compared toabout 260 μs for a 2-hydroxyethyl methacrylate (HEMA).

In another example, a polymer matrix comprising a compound with achlorine group with the following structure can be used to increase thelifetime of a porphyrin dye to about 310 μs compared to about 260 μs fora 2-hydroxyethyl methacrylate (HEMA).

In an embodiment, the intiator may be selected from one or morecompounds including irgacure Series (UV), Azobisisobutyronitrile (AIBN)(thermal), Ammonium Persulfate (APS) (thermal), and mixtures thereof.

In an embodiment, the polymer scaffold may have pore sizes of 0.1 μm-200μm. In an aspect, the polymer scaffold may have pore sizes of 5 μm-150μm. In an aspect, the polymer scaffold may have pore sizes of 10 μm-100μm.

Luminescent Sensing Compounds

Luminescent sensing compounds can include luminescent dyes, luminescentsensing molecules, proteins (e.g., chemically bound to a reporter dye),quantum dots, and/or any other moiety suitable to produce a signal inresponse to the presence of an analyte. Such a signal can correspond toa quantity and/or concentration of analyte. In some embodiments, theluminescent dye can operable to emit a luminescent signal in response toa secondary analyte, the quantity and/or concentration of which can beinfluenced by a reaction with an analyte of interest. For example, anoxygen-sensitive luminescent compound can chemically bound to orphysically associated with an oxidase configured to react with theanalyte of interest (e.g., glucose oxidase, lactate oxidase, etc.). Insuch an embodiment, the oxygen-sensitive luminescent compound can emit aluminescent signal that can be correlated to the analyte of interest(e.g., glucose, lactose, etc.). U.S. Pat. No. 9,375,494, entitled“Oxygen sensors,” issued on Jun. 28, 2016 and U.S. patent applicationSer. No. 15/855,555, entitled “Near-IR Glucose Sensors,” filed Dec. 27,2017, the entire disclosure of each of which is incorporated herein byreference, describes some suitable luminescent sensing compounds.

As discussed above, luminescent sensing compounds can be chemically(e.g., covalently or non-covalently) bound to and/or physically bound orembedded in a polymer and/or polymer scaffold. In some embodimentsdifferent luminescent sensing compounds can be chemically and/orphysically bound to different polymers that make up a one-piece polymerscaffold.

Luminescent sensing compounds can also include a polymer and/or bepolymerized. Similarly stated, a polymer scaffold can include or be madeup of one or more polymerized luminescent sensing compounds. In otherembodiments, polymer making up a polymer scaffold of the sensor can be adifferent polymer composition from the polymer of or containing theluminescent sensing compound.

As discussed in further detail herein, the intensity and/or lifetime ofa luminescent sensing compound can be altered based on a composition ofa polymer matrix. In some embodiments, by altering the polymer matrixwith short-lifetime-based luminescent sensing compounds (e.g.,luminescent sensing compounds having a lifetime in the range of 0 toabout 10 ns) (e.g., glucose-sensitive boronic acid dyes, pH-sensitivedyes, ion-sensitive dyes) the lifetime or intensity of theseshort-lifetime dyes may be shifted.

Some embodiments described herein relate to a 2-plex multi-analytesensor that includes, a single O₂-sensitive luminescent dye formulatedwith two different polymers, such that the sensor includes a firstsensor portion and a second sensor portion. In one example, the 2-plexmulti-analyte sensor is a glucose and O₂ sensor. For example, theO₂-sensitive luminescent dye in the first sensor portion is operable tosense oxygen directly. The second sensor portion includes theO₂-sensitive luminescent dye and a second sensing moiety, glucoseoxidase, for detection of glucose. The reaction of glucose via enzymaticinteraction with glucose oxidase causes O₂ to be proportionally consumedand converted to H₂O₂. The reduction of O₂ in the vicinity of the enzymeis measured by the second sensor portion. Each dye-polymer formulationcan have a different lifetime, such that signals from the differentdye-polymer formulations can be distinguished.

In another embodiment, a 4-plex sensor can be used to measure fouranalytes. Such a sensor can include, for example, two different analytesensitive luminescent dyes with non-overlapping excitation/emissionspectrums. Each of the analyte sensitive luminescent dyes can beformulated with two polymers and another sensing moiety or catalystconfigured to cause the analytes of interest to react, causing a changein the analyte to which the luminescent dyes are sensitive (e.g.,oxidases for O₂ sensitive dyes). Such a sensor can be operable to emittwo signals distinguishable by their emission spectrums and two signalsdistinguishable by their temporal signatures. In one example, themulti-analyte sensor is configured for sensing O₂, glucose (usingglucose oxidase), lactate (using lactate oxidase), and pyruvate (usingpyruvate oxidase).

Any other combination of luminescent sensing compounds and polymers ispossible. For example, a 9-plex sensor can be constructed using threedifferent O₂-sensitive luminescent dyes with non-overlappingexcitation/emission spectrums and three different polymers, such thatthe sensor can emit three sets of three signals distinguishable byemission spectrum, where each signal from a set of signals having thesame emission spectrum is distinguishable by temporal signature.

FIG. 1 is a chart illustrating a luminescent glucose sensitive compoundhaving variable luminescent intensity depending on polymer matrix,according to an embodiment. FIG. 1 shows spectra of two 10 mM glucosesensors, utilizing the same glucose sensitive dye in two differentpolymer matrices. The excitation wavelength was 630 nm. The followingmonomers are used in one or more dye-polymer formulations depicted inFIG. 1, and elsewhere in the application.

The glucose-sensitive dye used in the sensors of FIG. 1 is as follows:

As shown in FIG. 1, the polymer formulation significantly alters theintensity of the luminescent sensing compound. In particular, a 90/10formulation of DMA/PEGDAAm causes the luminescent sensing compound tophosphoresce with surprising intensity—intensity that is approximatelytwice as a 60/40 HEMA/DMA polymer-luminescent sensing compoundformulation.

Example 1—Effect of Different Polymer Matrices on the Signal andResponse of a Particular Analyte-Sensitive Luminescent Sensing Compoundto an Analyte

Table 1, shown below, illustrates that a dye's sensitivity changes whenformulated with different polymers. The above glucose-sensitive dye wasformulated with polymers and then subjected to various concentrations ofglucose over time. The sensitivity is shown in Table 1 as the“Modulation (1200/150)” which represents the intensity of the sensor at200 mg/dL divided by the intensity of the sensor at 50 mg/dL glucose.The sensor including HEMA has low response to glucose but when the dyewas formulated with AAm/Acryl-PEG/BIS, the dye had a greater than 90%increase in fluorescence intensity over the range of glucose tested.

TABLE 1 Modulation Formulation Dye (I200/50) HEMA/DMA (60/40), EGDA 2%,Glucose  9% Dye 10 mM, 50% sensitive dye AAm/Acryl-PEG (60/40), BISGlucose 93% (0.3%), Dye 10 mM, 25% sensitive dye

In some instances, a dye sensitive to one analyte may typically have asignificantly lower intensity than a dye sensitive to another analyte. Amulti-analyte sensor incorporating such dyes may result in the moreintense dye washing out the less intense dye, which may presentchallenges to deconvoluting signals associated with the different dyes.In some embodiments, therefore, dye-polymer formulations can be selectedto increase the intensity of the lower-intensity dye and/or decrease theintensity of the higher-intensity dye. Such a sensor, when exposed toanalytes, may produce luminescent signals that are within 5%, 10%, 25%,50%, or within any other suitable intensity of each other. Suchluminescent signals may then be more easily deconvoluted, for example,based on having different emission spectra and/or lifetimes.

FIG. 2, a chart showing the response of the formulations detailed belowin Table 1 to changes in glucose concentration, illustrates that thechoice of polymer can dramatically alter the modulation of a luminescentsensing compound. The blue trace changes intensity when exposed toconcentrations between 0 and 400 mg/dL. Accordingly, individuallyselecting dye-polymer formulations for luminescent sensing compounds cansignificantly improve and/or alter the performance of a luminescentsensing compound.

FIG. 2 compares the performance of one glucose sensitive dye in twodifferent polymer matrices, illustrating that the polymer can improvethe sensitivity of the dye, which facilitates data analysis. 50 mg/dLglucose was introduced at minute 59; 100 mg/dL glucose was introduced atminute 148; 200 mg/dL glucose was introduced at minute 187; and 400mg/dL glucose was introduced at minute 226. The data has been normalizedso that at 50 mg/dL glucose the intensity value has a numerical value ofone. The y-axis is the intensity normalized to 50 mg/dL glucose.Normalizing allows for us to compare two different sensors which havedifferent fluorescence intensity values.

FIG. 3 illustrates that luminescent intensity and luminescent lifetimecan be dramatically altered based on the choice of polymer.

FIG. 4 illustrates a multi analyte system, including an oxygen sensitiveluminescent compound and a glucose sensitive luminescent compound. Theperformance of an oxygen sensor was assessed in the presence ofdifferent polymers. The performance of a glucose sensor was alsoassessed in the presence of different polymers. The particularpolymer/sensor combination greatly affected the performance.

FIG. 5 is a block diagram of a system 100 operable to detectanalyte-dependent signals from a sensor 110. In some embodiments, thesensor 110 is a multi-analyte sensor operable to emit temporallydistinguishable signals. For example, the sensor 110 can be operable toemit two signals having the same or similar emission spectra, butdifferent lifetimes.

Sensor 110 can, for example, be implanted a few millimeters (e.g., 1-10mm) under the skin of a subject (not shown). Sensor 110 can include afirst sensor portion and a second sensor portion that are composed ofdifferent polymers but contain the same O₂-sensitive luminescent sensingcompound (or other suitable analyte-sensing compound). In one example,the O₂-sensitive luminescent dye is Pd-BP-AEME-4. Pd-BP-AEME-4 has thefollowing structure:

The first sensor portion and the second sensor portion of sensor 110 canbe formulated with different polymers such that signals emitted from thefirst sensor portion and the second sensor portion have differentluminescent lifetimes. Similarly stated, the first sensor portion can beconfigured to emit a long-lifetime signal, while the second sensorportion can be configured to emit a short-lifetime signal. Accordingly,multi-analyte sensor 110 is capable of emitting, in response to a singleexcitation light, two analyte-dependent optical signals with the sameemission wavelength, wherein the two analyte-dependent optical signalsmay be distinguished by their different lifetime decay curves, asillustrated, for example, in FIG. 6.

In one example, sensor 110 is a glucose and O₂ sensor. For example, theO₂-sensitive luminescent dye in the first sensor portion acts as a firstsensing moiety operable to directly measure O₂. The second sensorportion includes the O₂-sensitive luminescent dye and a second sensingmoiety, glucose oxidase, for detection of glucose. The reaction ofglucose via enzymatic interaction with glucose oxidase causes O₂ to beproportionally consumed and converted to H₂O₂. The reduction of O₂ inthe vicinity of the enzyme is measured by the O₂-sensitive luminescentdye in a second sensor portion. Each dye-polymer formulation can have adifferent lifetime, such that signals from the different dye-polymerformulations can be distinguished.

The analyte detection system 100 also includes an optical detector 115.The optical detector 115 can be a patch that can be placed on thesurface of the user's skin above or in close proximity to themulti-analyte sensor 110. The optical detector 115 includes a lightsource 120 operable to illuminate luminescent sensing compounds in thesensor 110, a detector 125 for collecting the emission light fromluminescent sensing compounds in the sensor 110, and suitable opticalcomponents 130 (e.g., lenses, optical filters, etc.), and acommunications port 135.

The light source 120 is operable to transmit an excitation light 140 tosensor 110. The light source 120 can be configured to generate lightthat is within the excitation wavelength range one or more luminescentsensing compounds of the sensor 110, such as an O₂-sensitive luminescentdye. In embodiments in which the sensor 110 includes multipleluminescent sensing compounds and/or multiple dye-polymer sensingportions, the light source 120 can be configured to simultaneouslyexcite multiple or all luminescent sensing compounds/dye-polymer sensingportions. In one example, light source 120 emits excitation light 140 inthe wavelength range of about 600 to about 650 nm. Suitable lightsources may include, but are not limited to, lasers, semi-conductorlasers, light-emitting diodes (LEDs), and organic LEDs.

Detector 125 is operable to detect emission light 142 from sensor 110.In particular, detector 125 is operable to detect light that is withinthe emission wavelength range of one or more luminescent sensingcompounds of the sensor 110, such as an O₂-sensitive luminescent dye. Asdiscussed in further detail herein, the detector 125 can be operable todetect optical signals emitted from includes multiple luminescentsensing compounds and/or multiple dye-polymer sensing portions,including optical signals having different temporal and/or emissionspectrum characteristics (e.g., a long-lifetime signal and ashort-lifetime signal). In one example, detector 125 may detect emissionlight 142 in the wavelength range of from about 750 to about 850 nm.Suitable detectors may include, but are not limited to, photodiodes,complementary metal-oxide-semiconductor (CMOS) detectors, andcharge-coupled device (CCD) detectors.

Detector 125 can be filtered (e.g., with dichroic filters or othersuitable filters) to measure the optical signals emitted within thewavelength ranges. Optical filters are one example of optical components130. However, optical components 130 may include any other types ofcomponents needed in optical detector 115.

Data received by the detector 125 can be transmitted to a computingdevice 160 that is operable to process such information. Computingdevice 160 can include a processor and a memory and may be any type ofcomputing device, such as a desktop computer, a laptop computer, atablet device, a mobile phone, a smartphone, and the like. A desktopapplication 162 or mobile app 162 resides on computing device 160 forprocessing any information from optical detector 115. As shown in FIG.5, the processing capability of analyte detection system 100 is externalto optical detector 115 that is operable to be disposed on the surfaceof the skin. It should be understood, however, that in otherembodiments, the detector 115 can include additional processingcapability (e.g., processors and/or memory) such that the detector 115itself may be operable to process and/or analyze signals received fromthe sensor 110. Furthermore, in other embodiments, data received by thedetector 115 can be processed via a remote server, on “the cloud,”and/or any other suitable computing environment.

Communications port 135 facilitates a communications link to lightsource 120 and detector 125. For example, communications port 135 can bea wired communications port, such as a USB or HDMI port, or a wirelesscommunications port, such as blue-tooth or Wi-Fi. Using communicationsport 135, the separate computing device 160 may be communicativelyconnected to light source 120 and detector 125 of optical detector 115.Namely, computing device 160 may be used to activate light source 120and to collect information from detector 125, wherein detector 125converts optical signals received from analyte sensor 110 to anelectrical and/or wireless signal output.

Computing device 160 may use desktop application 162 or mobile app 162to process any information from multi-analyte sensor 110. Namely,desktop application 162 or mobile app 162 may include any softwareand/or hardware components for processing any information frommulti-analyte sensor 110. In one example, desktop application 162 ormobile app 162 includes a deconvolution algorithm 164 suitable todeconvolute emission signals having different lifetimes and/or emissionspectra from sensor 110. The luminescent lifetime is a measure of thetime a luminescent material spends in the excited state before returningto the ground state by emitting a photon. A lifetime measurement isderived from the decay in the luminescent signal overtime. The lifetimesof luminophores can range from a few picoseconds to milliseconds. Thedeconvolution algorithm 164, therefore can be operable to determine aquantity and/or concentration of multiple analytes (e.g., oxygen,glucose, lactate, or pyruvate) by separating out signals havingdifferent decay rates (e.g., through frequency domain processing andanalysis).

FIG. 6 is a plot 400 of an example of the luminescent lifetime decaycurve of a multi-analyte sensor. Plot 400 indicates the combinedshort-lifetime and the long-lifetime components of the optical signalemitted by the multi-analyte sensor 110, and the deconvolutedshort-lifetime component. Namely, a curve 410 indicates the emissionintensity of the multi-analyte sensor, wherein the optical signalincludes emission from the long-lifetime component (e.g., O₂ sensingcomponent) and a short-lifetime component (e.g., glucose sensingcomponent) of the sensor. A curve 415 indicates the emission intensityof the short-lifetime component deconvoluted from the combined opticalsignal (i.e., curve 410) returned from multi-analyte sensor 110. Thearea of curve 410 highlighted in gray represents the long-lifetimecomponent of the sensor.

Table 2 below includes a list of sensor component formulations. Eachformulation includes Pd-BP-AEME-4 as a luminescent sensing compound (or“dye”). As shown in the column labeled tau0, the lifetime of the dye ina zero-oxygen environment in microseconds, the lifetime of theluminescent sensing compound varies dramatically and unexpectedlydepending on the polymers chemically and/or physically bound to theluminescent sensing compound. Because luminescent signals havingdifferent lifetimes can be deconvoluted as discussed in further detailherein, a sensor containing multiple Pd-BP-AEME-4-polymer portions canbe used to detect multiple analytes. In some embodiments, it can bedesirable to select dye-polymer formulations whose luminescent lifetimesvary by at least 10%, by at least 25%, by at least 60%, or by at least100% when formulating a multi-analyte sensor.

Table 2 further shows that the tau0 could be changed by changing thecomponents as well as the ratio of those components. For example, informulations with Component 1=hydroxyethyl methacrylate and Component2=ethylene glycol dimethacrylate, the wt % of ethylene glycol directlyimpacted the tau0 of the formulation. An increase in ethylene glycoldimethacrylate changed the tau0 from 268 μs to 279 μs. With the sameformulations, by keeping the wt % of ethylene glycol constant atapproximately 9.8, adding a Component 2=hydroxypropyl methacrylate andComponent 3=ethylene glycol methacrylate increased the tau0 from 279 μsto 297 μs. These examples offer some direct comparisons of the abilityto change components and ratios of the components to change the behaviorof the polymer. Overall, changing components and ratios of the polymerwhile utilizing the same dye resulted in tau0 measurements from 101 μsto 411.6 μs.

TABLE 2 wt % wt % wt % Component 1 Component 2 Component 3 cmpt 1 cmpt 2cmpt 3 Tau0 (μs) 2-hydroxyethyl 2,2,3,3,4,4,5,5-octafluoro- 95.23 4.77101.5 methacrylate 1,6-hexyldimethacrylate 2,2,3,3,4,4,4- 2-hydroxyethylethylene glycol 53.69 41.98 4.33 115.6 heptafluorobutyl methacrylatedimethacrylate methacrylate 2-carboxyethyl acrylate[2-(acryloyloxy)ethyl]trimethylammonium tetraethylene glycol 59.00 38.882.12 160.6 chloride dimethacrylate 2-carboxyethyl acrylate[2-(acryloyloxy)ethyl]trimethylammonium tetraethylene glycol 57.08 37.625.30 184.0 chloride dimethacrylate o-nitrobenzyl tetraethylene glycol90.98 9.02 185.4 methacrylate dimethacrylate [2- Polyurethane D640 (10%)N,N′- 83.64 16.24 0.12 186.6 (methacryloyloxy)ethyl]dimethyl-methylenebis(acrylamide) (3-sulfopropyl)ammonium hydroxide poly(ethyleneglycol) Polyurethane D640 (5%) 78.89 21.11 192.3 diacrylate (Mn = 700)2-carboxyethyl acrylate [2-(acryloyloxy)ethyl]trimethylammoniumtetraethylene glycol 43.14 41.08 15.78 197.2 chloride dimethacrylate2-carboxyethyl acrylate [2-(acryloyloxy)ethyl]trimethylammoniumtetraethylene glycol 53.91 35.52 10.57 197.8 chloride dimethacrylatepoly(ethylene glycol) Polyurethane D640 (5%) 91.79 8.21 201.8 diacrylate(Mn = 700) acrylamide Polyurethane D640 (5%) N,N′- 77.84 22.06 0.10204.1 methylenebis(acrylamide) poly(ethylene glycol) Polyurethane D640(5%) 81.65 18.35 206.4 diacrylamide (Mn = 3700) [2- Polyurethane D640(10%) N,N′- 80.15 19.62 0.22 210.2 (methacryloyloxy)ethyl]dimethyl-methylenebis(acrylamide) (3-sulfopropyl)ammonium hydroxide poly(ethyleneglycol) Polyurethane D640 (5%) 73.66 26.34 213.4 diacrylate (Mn = 700)o-nitrobenzyl ethylene glycol 91.29 8.71 215.2 methacrylatedimethacrylate poly(ethylene glycol) Polyurethane D640 (5%) 78.87 21.13217.6 diacrylate (Mn = 700) poly(ethylene glycol) Polyurethane D640 (5%)83.29 16.71 221.7 diacrylate (Mn = 700) 2-hydroxyethyl tetraethyleneglycol 89.83 10.17 223.6 methacrylate dimethacrylate [2- PolyurethaneD640 (5%) N,N′- 77.84 22.06 0.10 225.0 (methacryloyloxy)ethyl]dimethyl-methylenebis(acrylamide) (3-sulfopropyl)ammonium hydroxide/acrylamide(1:1) poly(ethylene glycol) Polyurethane D640 (10%) 71.36 28.64 233.5diacrylate (Mn = 700) 2-carboxyethyl acrylate[2-(acryloyloxy)ethyl]trimethylammonium tetraethylene glycol 47.62 31.3821.01 235.8 chloride dimethacrylate 2-hydroxyethyl tetraethylene glycol2-methacryloyloxyethyl 80.15 18.14 1.71 242.6 methacrylatedimethacrylate phosphorylcholine 2-hydroxyethyl tetraethylene glycol95.15 4.85 250.3 methacrylate dimethacrylate 2-hydroxyethyltetraethylene glycol 69.61 30.39 251.7 methacrylate dimethacrylate2-hydroxyethyl tetraethylene glycol 94.91 5.09 252.9 methacrylatedimethacrylate 2-hydroxyethyl tetraethylene glycol 97.96 2.04 253.1methacrylate dimethacrylate 2-hydroxyethyl tetraethylene glycol2-methacryloyloxyethyl 96.63 2.68 0.69 254.7 methacrylate dimethacrylatephosphorylcholine 2,2,3,3,4,4,4- ethylene glycol 96.31 3.69 255.5heptafluorobutyl dimethacrylate methacrylate 2-hydroxyethyltetraethylene glycol 98.00 2.00 256.7 methacrylate dimethacrylate laurylmethacrylate tetraethylene glycol 2-methacryloyloxyethyl 55.90 38.325.78 262.2 dimethacrylate phosphorylcholine 2-(tert-butylamino)ethylethylene glycol 94.40 5.60 263.8 methacrylate dimethacrylate laurylmethacrylate tetraethylene glycol 2-methacryloyloxyethyl 86.52 11.242.24 265.6 dimethacrylate phosphorylcholine 2-hydroxyethyl ethyleneglycol 95.10 4.90 267.9 methacrylate dimethacrylate 2,2,3,3,4,4,4-ethylene glycol 83.93 16.07 268.3 heptafluorobutyl dimethacrylatemethacrylate 2-hydroxyethyl ethylene glycol n-hexyl acrylate 77.88 14.967.16 272.6 methacrylate dimethacrylate 2,2,3,4,4,4- ethylene glycol96.13 3.87 273.0 hexafluorobutyl dimethacrylate methacrylate acrylamideN,N′- 99.86 0.14 275.0 methylenebis(acrylamide) 2,2,3,3,4,4,4-poly(ethylene glycol) 82.77 17.23 277.5 heptafluorobutyl diacrylate (Mn= 700) methacrylate 2-hydroxyethyl ethylene glycol 90.18 9.82 279.3methacrylate dimethacrylate 2-hydroxyethyl 2-fluoroethyl methacrylatepoly(ethylene glycol) 75.23 19.50 5.27 279.4 methacrylate diacrylate (Mn= 700) 2-hydroxyethyl N,N-dimethylacrylamide ethylene glycol 73.40 16.629.98 282.1 methacrylate dimethacrylate 1,1,1,3,3,3- tetraethylene glycol91.79 8.21 284.5 hexafluoroisopropyl dimethacrylate acrylate2,2,3,3,4,4,4- poly(ethylene glycol) 91.53 8.47 287.3 heptafluorobutyldiacrylate (Mn = 700) methacrylate 2,2,3,3,4,4,4- ethylene glycol2,2,2-trifluoroethyl 68.55 16.40 15.05 288.5 heptafluorobutyldimethacrylate methacrylate methacrylate 2-hydroxyethyl ethylene glycolhydroxypropyl 76.85 14.76 8.40 289.5 methacrylate dimethacrylatemethacrylate 2-hydroxyethyl n-hexyl acrylate ethylene glycol 78.47 12.998.54 289.8 methacrylate dimethacrylate 2-hydroxyethyl ethylene glycolhydroxypropyl 81.29 9.83 8.88 291.1 methacrylate dimethacrylatemethacrylate 2-hydroxyethyl n-hexyl acrylate ethylene glycol 74.46 15.4110.13 291.9 methacrylate dimethacrylate 2-hydroxyethyl hydroxypropylethylene glycol 63.42 26.73 9.86 297.2 methacrylate methacrylatedimethacrylate 2-hydroxyethyl ethylene glycol 2-methacryloyloxyethyl80.71 17.57 1.72 298.7 methacrylate dimethacrylate phosphorylcholine2,2,3,3,4,4,4- ethylene glycol 96.13 3.87 303.4 heptafluorobutyldimethacrylate methacrylate 2,2,2-trifluoroethyl poly(ethylene glycol)98.10 1.90 307.1 methacrylate diacrylate (Mn = 700) 2,2,3,3,4,4,4-tetraethylene glycol 95.98 4.02 307.2 heptafluorobutyl dimethacrylatemethacrylate 2,2,3,3-tetrafluoropropyl poly(ethylene glycol) 95.45 4.55307.3 methacrylate diacrylate (Mn = 700) 3-chloro-2-hydroxypropyltetraethylene glycol 98.20 1.80 307.7 methacrylate dimethacrylate2-hydroxyethyl 2-fluoroethyl methacrylate poly(ethylene glycol) 56.0338.73 5.23 308.3 methacrylate diacrylate (Mn = 700) 2,2,2-trifluoroethylpoly(ethylene glycol) 95.25 4.75 309.8 methacrylate diacrylate (Mn =700) 2,2,3,3,4,4,4- trimethylolpropane 95.87 4.13 311.9 heptafluorobutyltriacrylate methacrylate 2,2,2-trifluoroethyl 2-hydroxyethyl ethyleneglycol 78.13 17.39 4.48 314.7 methacrylate methacrylate dimethacrylate2,2,2-trifluoroethyl ethylene glycol 98.25 1.75 318.2 methacrylatedimethacrylate 2,2,3,3-tetrafluoropropyl ethylene glycol 91.53 8.47319.4 methacrylate dimethacrylate 2,2,2-trifluoroethyl ethylene glycol86.66 13.34 319.7 methacrylate dimethacrylate 2,2,2-trifluoroethyltetraethylene glycol 98.18 1.82 320.1 methacrylate dimethacrylate2-hydroxyethyl methyl methacrylate tetraethylene glycol 47.45 41.8110.74 321.2 methacrylate dimethacrylate 2,2,2-trifluoroethyl ethyleneglycol 91.17 8.83 322.8 methacrylate dimethacrylate 2-fluoroethylpoly(ethylene glycol) 69.43 30.57 325.4 methacrylate diacrylate (Mn =700) methyl methacrylate ethylene glycol 94.47 5.53 325.6 dimethacrylate2-fluoroethyl tetraethylene glycol 95.08 4.92 327.9 methacrylatedimethacrylate 2,2,3,4,4,4- ethylene glycol 88.12 11.88 329.7hexafluorobutyl dimethacrylate methacrylate 2,2,3,4,4,4- ethylene glycol92.17 7.83 330.5 hexafluorobutyl dimethacrylate methacrylate2,2,2-trifluoroethyl tetraethylene glycol 95.44 4.56 335.8 methacrylatedimethacrylate 2-fluoroethyl 2-hydroxyethyl poly(ethylene glycol) 48.2546.53 5.22 336.4 methacrylate methacrylate diacrylate (Mn = 700)2,2,3,3,4,4,4- 1,6-hexanediol diacrylate 96.94 3.06 336.7heptafluorobutyl methacrylate methyl methacrylate tetraethylene glycol94.26 5.74 339.6 dimethacrylate methyl methacrylate tetraethylene glycol88.62 11.38 340.3 dimethacrylate 2-fluoroethyl tetraethylene glycol98.03 1.97 341.0 methacrylate dimethacrylate 2,2,3,4,4,4- 2-hydroxyethylethylene glycol 80.30 15.66 4.04 342.0 hexafluorobutyl methacrylatedimethacrylate methacrylate 2,2,2-trifluoroethyl ethylene glycol 95.614.39 342.1 methacrylate dimethacrylate 2-fluoroethyl poly(ethyleneglycol) 94.87 5.13 343.6 methacrylate diacrylate (Mn = 700)2,2,3,3,4,4,4- poly(ethylene glycol) 95.80 4.20 344.1 heptafluorobutyldiacrylate (Mn = 700) methacrylate 2-fluoroethyl poly(ethylene glycol)79.57 20.43 344.3 methacrylate diacrylate (Mn = 700)2,2,2-trifluoroethyl 1,6-hexanediol diacrylate 96.69 3.31 344.9methacrylate ethylene glycol ethylene glycol 95.15 4.85 347.0dicyclopentenyl ether dimethacrylate methacrylate 2,2,3,4,4,4- ethyleneglycol 92.90 7.10 348.3 hexafluorobutyl dimethacrylate methacrylate2-fluoroethyl poly(ethylene glycol) 97.95 2.05 348.4 methacrylatediacrylate (Mn = 700) 2-fluoroethyl 2-hydroxyethyl poly(ethylene glycol)76.41 18.42 5.16 348.5 methacrylate methacrylate diacrylate (Mn = 700)2-fluoroethyl poly(ethylene glycol) 82.96 17.04 351.0 methacrylatediacrylate (Mn = 700) 2-fluoroethyl poly(ethylene glycol) 89.76 10.24352.6 methacrylate diacrylate (Mn = 700) 2,2,2-trifluoroethyl2,2,3,3,4,4,4- ethylene glycol 74.51 21.21 4.28 354.5 methacrylateheptafluorobutyl dimethacrylate methacrylate 2,2,2-trifluoroethyltrimethylolpropane 95.33 4.67 362.1 methacrylate triacrylate2,2,2-trifluoroethyl 1,6-hexanediol diacrylate 96.52 3.48 363.1methacrylate ethylene glycol tetraethylene glycol 94.97 5.03 364.5dicyclopentenyl ether dimethacrylate methacrylate benzyl methacrylateethylene glycol 95.05 4.95 366.0 dimethacrylate 2-fluoroethyl ethyleneglycol 95.26 4.74 391.2 methacrylate dimethacrylate pentafluorobenzylethylene glycol 92.27 7.73 391.4 methacrylate dimethacrylatepentafluorobenzyl ethylene glycol 98.48 1.52 411.0 methacrylatedimethacrylate pentafluorobenzyl ethylene glycol 96.18 3.82 411.6methacrylate dimethacrylate pentafluorobenzyl poly(ethylene glycol)91.65 8.35 413.9 methacrylate diacrylate (Mn = 700)

Example 4—Oxygen Sensors

Oxygen-sensitive polymers were synthesized with the dyes and wt % of thedifferent monomers, crosslinkers, and/or polymers described in Table 2.For the composition of Component 1=2,2,2-trifluoroethyl methacrylate(95.2%), Component 2=poly(ethylene glycol) diacrylate (M_(n)=700)(4.8%), the following protocol was used. The polymer composition (62.5μL) was mixed based on the weight percentages above. The solvent and dyemixture (62.5 μL) was prepared by adding2,2′-Azorbis(2,4-dimethylvaleronitrile) (0.6 mg), dimethyl sulfoxide(49.4 μL), and Pd-BP-AEME-4 (10 mM in dimethylsulfoxide, 12.5 μL). Thepolymer composition (62.5 μL) and solvent and dye mixture (62.5 μL),were combined and put into a glass mold with a 0.75 mm wide Teflonspacer. The solution was then polymerized by heating at 60° C. for 120minutes. The material was then removed from the mold, placed in waterovernight and cut into smaller sizes for testing.

Other combinations of polymers were created using a similar method asdescribed above. Co-solvents were chosen based on solubility and werecombinations of ethanol, ethylene glycol, dimethyl sulfoxide,tetrahydrofuran, water, phosphate buffered saline, dimethylformamide,N-methyl-2-pyrrolidone. Ultra-violet initiators and heat initiators of2,2′-Azorbis(2,4-dimethylvaleronitrile),2,2-dimethoxy-2-phenylacetophenone,2,2′-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride,1-Hydroxycyclohexyl phenyl ketone,2-Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone, andazobisisobutyronitrile were used alone or in combination with anotherinitiator depending on the component combinations and polymerizationapproach (UV or heat). The polymers were synthesized with between 30-90%polymer composition balanced with the solvent and dye mixture.

After polymerization, the sensors were equilibrated in phosphatebuffered saline (20 mM) and tested in vitro by bubbling pure nitrogen at37° C. until an equilibrium was reached. The phosphorescent lifetime attau0 were measured with a custom optical reader. The tau0 is defined asthe phosphorescent lifetime at 0% oxygen in solution at 37° C. The tau0is presented in Table 2.

Table 2 shows that the tau0 could be changed by changing the componentsas well as the ratio of those components. For example, in formulationswith Component 1=hydroxyethyl methacrylate and Component 2=ethyleneglycol dimethacrylate, the wt % of ethylene glycol directly impacted thetau0 of the formulation. An increase in ethylene glycol dimethacrylatechanged the tau0 from 268 μs to 279 μs. With the same formulations, bykeeping the wt % of Component 3=ethylene glycol constant atapproximately 9.8, adding a Component 2=hydroxypropyl methacrylateincreased the tau0 from 279 μs to 297 μs. These examples offer somedirect comparisons of the ability to change components and ratios of thecomponents to change the behavior of the polymer. Overall, changingcomponents and ratios of the polymer while utilizing the same dyeresulted in tau0 measurements from 101 μs to 411.6 μs.

Example 3-4-Plex Sensor

As discussed above, a luminescent sensing compound can be formulatedwith different polymers to produce different sensing compounds havingdifferent luminescent lifetimes, which can be deconvoluted to detect twodifferent analytes. Example 2 illustrates a 4-plex sensor.

A first sensor portion can be composed of a first polymer matrix and afirst O₂-sensitive luminescent dye, such as Pd-BP-AEME-4. A secondsensor portion composed of a second polymer matrix and the firstO₂-sensitive luminescent dye. A third sensor portion can be composed ofthe third polymer matrix and a second O₂-sensitive luminescent dye, suchas QMAP. A fourth sensor portion can be composed of a fourth polymermatrix and the second O₂-sensitive luminescent dye. In some embodiments,the first polymer matrix can be the same or similar to the third polymermatrix, and/or the second polymer matrix can be the same or similar tothe fourth polymer matrix. The first, sensor portion, the second sensorportion, the third sensor portion, and the fourth sensor portion caneach be portions of a single sensor. Similarly stated, the sensor can bea single body having different dye-polymer portions configured to beimplanted into a subject.

The formulations of the first sensor portion and the second sensorportion of multi-analyte sensor are selected to yield a long-lifetimesignal and a short-lifetime signal from the first O₂-sensitiveluminescent dye (e.g., Pd-BP-AEME-4) for monitoring a first analyte anda second analyte. Accordingly, multi-analyte sensor is capable ofemitting, in response to a first excitation light, two analyte-dependentoptical signals with the same emission wavelength, wherein the twoanalyte-dependent optical signals may be distinguished by theirdifferent lifetime characteristics.

The formulations of the third sensor portion and the fourth sensorportion of multi-analyte sensor are selected to yield a long-lifetimesignal and a short-lifetime signal from the second O₂-sensitiveluminescent dye for monitoring a third analyte and a fourth analyte.Accordingly, multi-analyte sensor is capable of emitting, in response toa second excitation light, two analyte-dependent optical signals withthe same emission wavelength, wherein the two analyte-dependent opticalsignals may be distinguished by their different lifetimecharacteristics.

In one example, multi-analyte sensor is an O₂, glucose, lactate, andpyruvate sensor. For example, a first O₂-sensitive luminescent dye inthe first sensor portion acts as a first sensing moiety for sensing O₂.The second sensor portion includes the first O₂-sensitive luminescentdye and a second sensing moiety, glucose oxidase, for detection ofglucose. The third sensor portion includes a second O₂-sensitiveluminescent dye and a third sensing moiety, lactate oxidase, fordetection of lactate. The fourth sensor portion includes the secondO₂-sensitive luminescent dye and a fourth sensing moiety, pyruvateoxidase, for detection of pyruvate.

In some embodiments, the first O₂-sensitive dye and the secondO₂-sensitive dye can have different excitation wavelengths. Similarlystated, a reader can be configured to emit excitation light in twowavelengths, one wavelength to excite the first O₂-sensitive dye, and asecond wavelength to excite the second O₂ sensitive dye. In some suchembodiments, the first O₂-sensive dye and the second O₂-sensitive dyecan be excited simultaneously. Similarly, the reader can include one ormore detectors operable to detect emission light across emission spectrafor both the first O₂-sensive dye and the second O₂-sensitive dye. Insome such embodiments, the reader can be configured to detect emissionsignals emitted simultaneously from first O₂-sensive dye and the secondO₂-sensitive dye.

FIG. 7A is a plot 700 of an example of the emission intensity of the4-plex multi-analyte sensor. Plot 700 indicates the combinedshort-lifetime and long-lifetime components of a first optical signalreturned from multi-analyte sensor, and the deconvoluted short-lifetimecomponent. Namely, a curve 710 indicates the emission intensity of theoptical signal returned from multi-analyte sensor 110, wherein theoptical signal includes emission from both the long-lifetime component(e.g., O₂ component) and the short-lifetime component (e.g., glucosecomponent) of the sensor. A curve 715 indicates the emission intensityof the short-lifetime component deconvoluted from the combined opticalsignal (i.e., curve 710) returned from multi-analyte sensor 110. Thearea of curve 710 highlighted in gray represents the long-lifetimecomponent of the sensor.

FIG. 7B is a plot 750 of an example of the emission intensity of the4-plex multi-analyte sensor. Plot 750 indicates the combinedshort-lifetime and long-lifetime components of a second optical signalreturned from multi-analyte sensor and the deconvoluted short-lifetimecomponent. Namely, a curve 760 indicates the emission intensity of theoptical signal returned from multi-analyte sensor 110, wherein theoptical signal includes emission from both the long-lifetime component(e.g., pyruvate component) and the short-lifetime component (e.g.,lactate component) of the sensor. A curve 765 indicates the emissionintensity of the short-lifetime component deconvoluted from the combinedoptical signal (i.e., curve 760) returned from multi-analyte sensor 110.The area of curve 760 highlighted in gray represents the long-lifetimecomponent of the sensor.

Example 4—9-Plex Sensor

Table 3 below shows an example of a design layout for multiplexing thesimultaneous detection of nine analytes using three O₂-sensitiveporphyrin dyes and three different polymers. Each porphyrin dye, P1, P2,and P3 can have a different excitation and/or emission spectra and caneach be formulated with three different polymers, H1, H2, and H3,causing temporal shifts in characteristic emission for each of the dyes.Each dye-polymer combination is paired with an individual enzyme orother suitable analyte-reactive agent (except for the analysis of O₂)for the analysis of a specific analyte (e.g., alcohol, bilirubin,lactate, ascorbate, cholesterol, glucose, histamine, and pyruvate).

TABLE 3 Example 9-plex multi-analyte sensor P1 P2 P3 H1 Oxygen LactateGlucose H2 Alcohol Ascorbate Histamine H3 Bilirubin Cholesterol Pyruvate

Further, using the 9-plex sensor design described with reference toTable 3 above, three “channels” may be dedicated to detecting a singleanalyte. Table 4 below shows an example of a design layout, whereinthree “channels” are dedicated to detecting O₂ for improved accuracy foran O₂-based sensing platform.

TABLE 4 Example 9-plex sensor with dedicated O2 channels P1 P2 P3 H1Oxygen Lactate Glucose H2 Alcohol Ascorbate Histamine H3 BilirubinOxygen Oxygen

Table 5 below shows another example of a design layout, wherein threechannels are dedicated to detecting any three analytes for improvedaccuracy through repetition.

TABLE 5 Example 9-plex sensor with dedicated 3-analyte channels P1 P2 P3H1 Oxygen Lactate Glucose H2 Glucose Oxygen Lactate H3 Lactate GlucoseOxygen

Example 5—Dual Sensors

TABLE 6 Total Volume Component 1/Component 2/ Enzymatic ComponentsFormulation (uL) Component 3 Cosolvents Dye (w/v %) Lactate 500HEMA/HPMA/EGDMA 0.67M 1- 1 mM Pd-BP- 2.1% (w/v) LOx from Sensor(63.4/26.7/9.8% w/w of Methyl-2- AEME-4 in Aerococcus viridans monomerand/or polymer content pyrrolidinone NMP of major components) (NMP)Coating 200 0.88 mM polycarbonate 15.7M NA NA in methylene chlorideMethylene chloride Oxygen 230 PUD640 (5% wt/v in 9:1 0.45M NMP 1.3 mMPd- NA Sensor ethanol/water)/PEGDA700 BP-AEME -4 (16.7/83.3% w/w of inNMP polymer content only)

Table 6 outlines the synthesis components of a dual sensor with alactate sensor portion, passive layer (coating) and oxygen sensorportion. The first sensing layer, including lactate oxidase, of alayered lactate sensor was prepared as follows (Table 6): Irgacure 651(Sigma-Aldrich, HEMA (Polysciences), HPMA (Sigma-Aldrich), EGDMA(Sigma-Aldrich), Pd-BMAP-AEME-4 (U.S. Pat. No. 9,375,494), and NMP(N-Methyl-2-pyrrolidone, Sigma-Aldrich) were added together and mixedwell to form solution 1. 2-Aminoethylmethacrylate hydrochloride (AEMA,Sigma-Aldrich), LOx (Lactate Oxidase, Sekisui) from Aerococcus viridans,and PBS (phosphate buffered saline, 20 mM) were mixed together to formsolution 2. Solution 1 was added to solution 2 to get a mixture withfinal concentrations of Irgacure 651 (19.5 mM), HEMA (3.63 M), HPMA(1.35 M), EGDMA (0.37 M), AEMA (0.56 mM), Pd-BMAP-AEMA-4 (1 mM), NMP(0.67 M) and enzymatic component (LOx, 2.1% wt/v) in 20 mM PBS such thatthe PBS volume was 18.8% of the total volume mixture. The mixture waspolymerized and prepared for the coating process.

Application of a Coating to the First Sensing Layer

A coating was applied to the first sensing layer including lactateoxidase prepared above. Water on the surface of the lactate sensinglayer was removed. The sensing layers were coated with a polycarbonatesolution ((VWR) 0.88 mM in methylene chloride (Sigma-Aldrich)) anddried. After coating, the sensors were stored in PBS (20 mM) solution.

Additional passive layers were prepared as described above, using thetubings and coatings and combinations thereof shown in Table 7.

Application of a Second Sensing Layer

A second sensing layer, functioning as a reference, was applied to thecoating on the first sensing layer prepared above.

Irgacure 651 (19.5 mM), PEGDA700 (poly(ethylene glycol) diacrylateaverage M_(n) 700, 83.3% w/w of polymer content only, Sigma-Aldrich),Pd-BMAP-AEME-4 (1.3 mM, prepared as described above), NMP (0.45M), andPU D640 (5 wt/v % in ethanol/water 9:1 v/v, 16.7% w/w of polymer contentonly, AdvanSource Biomaterials Inc.) were mixed such that theethanol/water solution was 72% (v/v) to form the oxygen reference layer(solution 3) solution. To incorporate the oxygen reference solution onthe passive layer, the water on the surface of the passive layer wasremoved. The coating was then applied to the surface. Coated sensorswere then stored in PBS.

Table 7 shows additional examples of lactate/O2 sensors and Table 8shows additional examples of oxygen/oxygen sensors. Displayed in thetable are the weight percentages of the major monomer and/or polymercomponents with respect to each other. For testing, lactate/oxygen andoxygen/oxygen sensors were placed in a customized test fixture withcontrollable oxygen levels. All sensors were tested in 500 mL of PBS andallowed to equilibrate at 37° C. An oxygen modulation was performed onthe sensors. Automated gas mixing systems were used to modulate oxygenconcentration at stepwise decreases in concentration. Sensors weretested at 0, 0.25, 0.5, 1, 2, 5, 10, 21% oxygen. At each oxygenconcentration, the sensor phosphorescence signal was equilibrated andphosphorescent lifetimes from each sensing portion was calculated usingcustom algorithms. Response curves were generated by averaging thephosphorescence signal of the last 2 minutes of each step prior tochanges in oxygen. The tau0 reported in Tables 7 and 8 refer to thecalculated phosphorescent decay at 0% oxygen. Higher ratios (>1.6)between the two sensing layers are desirable for accurate temporalseparation and measurements from each layer.

TABLE 7 Ratio of tau0 for Lactate Sensing wt % wt % wt % tau0Layer/Oxygen Component 1 Component 2 Component 3 cmpt 1 cmpt 2 cmpt 3Dye or Sensor (us) Sensing Layer 2- hydroxypropyl ethylene 63.42 26.739.86 Pd-BP-AEME-4 307.88 2.26 hydroxyethyl methacrylate glycolmethacrylate dimethacrylate Polyurethane poly(ethylene 16.71 83.29Pd-BP-AEME-1 136.09 D640 (5%) glycol) diacrylate 2- hydroxypropylethylene 63.42 26.73 9.86 Pd-BP-AEME-4 278.41 1.75 hydroxyethylmethacrylate glycol methacrylate dimethacrylate Polyurethanepoly(ethylene 16.71 83.29 Pd-BP-AEME-4 158.68 D640 (5%) glycol)diacrylate 2- hydroxypropyl ethylene 63.42 26.73 9.86 Pd-BP-AEME-4309.58 1.86 hydroxyethyl methacrylate glycol methacrylate dimethacrylatePolyurethane poly(ethylene 16.71 83.29 Pd-BP-AEME-4 166.76 D640 (5%)glycol) diacrylate 2- hydroxypropyl ethylene 63.42 26.73 9.86Pd-BP-AEME-4 325.15 1.82 hydroxyethyl methacrylate glycol methacrylatedimethacrylate Polyurethane poly(ethylene 16.71 83.29 Pd-BP-AEME-4178.37 D640 (5%) glycol) diacrylate 2- hydroxypropyl ethylene 63.4226.73 9.86 Pd-BP-AEME-4 276.67 1.86 hydroxyethyl methacrylate glycolmethacrylate dimethacrylate Polyurethane poly(ethylene 16.71 83.29Pd-BP-AEME-4 149.10 D640 (5%) glycol) diacrylate 2- hydroxypropylethylene 63.42 26.73 9.86 Pd-BP-AEME-4 306.88 1.94 hydroxyethylmethacrylate glycol methacrylate dimethacrylate Polyurethanepoly(ethylene 16.71 83.29 Pd-BP-AEME-4 158.49 D640 (5%) glycol)diacrylate 2- hydroxypropyl ethylene 63.42 26.73 9.86 Pd-BP-AEME-4294.50 2.12 hydroxyethyl methacrylate glycol methacrylate dimethacrylatePolyurethane poly(ethylene 16.71 83.29 Pd-BP-AEME-4 138.72 D640 (5%)glycol) diacrylate 2- hydroxypropyl ethylene 63.42 26.73 9.86Pd-BP-AEME-4 321.63 1.73 hydroxyethyl methacrylate glycol methacrylatedimethacrylate Polyurethane poly(ethylene 16.71 83.29 Pd-BP-AEME-4185.55 D640 (5%) glycol) diacrylate 2- hydroxypropyl ethylene 63.4226.73 9.86 Pd-BP-AEME-4 325.58 1.80 hydroxyethyl methacrylate glycolmethacrylate dimethacrylate Polyurethane poly(ethylene 16.71 83.29Pd-BP-AEME-4 180.72 D640 (5%) glycol) diacrylate 2- hydroxypropylethylene 63.42 26.73 9.86 Pd-BP-AEME-4 278.95 1.71 hydroxyethylmethacrylate glycol methacrylate dimethacrylate Polyurethanepoly(ethylene 21.13 78.87 Pd-BP-AEME-4 163.01 D640 (5%) glycol)diacrylate 2- hydroxypropyl ethylene 63.42 26.73 9.86 Pd-BP-AEME-4308.79 1.68 hydroxyethyl methacrylate glycol methacrylate dimethacrylatePolyurethane poly(ethylene 21.13 78.87 Pd-BP-AEME-4 183.47 D640 (5%)glycol) diacrylate

TABLE 8 wt % wt % wt % tau0 Ratio of tau0 for Component 1 Component 2Component 3 cmpt 1 cmpt 2 cmpt 3 Dye or Sensor (us) Layer 1/Layer 2 2-hydroxypropyl ethylene glycol 63.42 26.73 9.86 Pd-BP-AEME-4 304.08 2.32hydroxyethyl methacrylate dimethacrylate methacrylate Polyurethanepoly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-1 130.93 D640 (5%)diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.73 9.86Pd-BP-AEME-4 311.98 1.66 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4187.76 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 313.13 1.83 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4171.33 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 315.64 1.81 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4174.61 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 282.33 1.89 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4149.26 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 316.04 1.96 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4161.02 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 295.42 2.27 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4130.13 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 328.34 1.74 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4188.27 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 330.33 1.75 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 16.71 83.29 Pd-BP-AEME-4188.33 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 334.30 1.64 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 21.13 78.87 Pd-BP-AEME-4204.31 D640 (5%) diacrylate 2- hydroxypropyl ethylene glycol 63.42 26.739.86 Pd-BP-AEME-4 308.35 1.69 hydroxyethyl methacrylate dimethacrylatemethacrylate Polyurethane poly(ethylene glycol) 21.13 78.87 Pd-BP-AEME-4182.42 D640 (5%) diacrylate

Example 6—Particle Sensors

Particles with dye were synthesized by mixing the components listed inTable 9. The components were added to a beaker and the mixture wassonicated on ice for 10 minutes. The solution was then covered withaluminum foil and deoxygenated with argon for at least 10 minutes. Thebeaker was covered with Saran wrap, placed on a stir plate directlyunder a UV lamp. The mixture was left to stir for 2.5 hours under UVexposure. After 2.5 hours, unreacted reagents and surfactants wereremoved by adding 1 N HCl until the pH was approximately 3. Acetone wasadded to take 70% of the total volume and the mixture was centrifugedfor 15 minutes at approximately 6500 rpm. Supernatant was removed andpellet was resuspended in 5 mL of 0.5 N HCl. The removal of supernatantwas repeated for a total of 5 times. After the last wash, the particleswere either dried or resuspended in water and stored away from light.

Particles from Table 9 were incorporated into a polymer of Component1=hydroxyethyl methacrylate (98%) and Component 2=tetra(ethylene glycol)dimethacrylate (2%). The host polymer did not contain any dye itself andthat volume was replaced with dimethyl sulfoxide. The particles wereincorporated at an amount between 5 to 25 mg particles per 100 μL ofpre-polymer solution of Component 1, Component 2, initiator, andco-solvents. At the bottom of Table 9 are the results afterincorporation Particles 1, 2, and 3 into the host polymer. Theincorporation of particles synthesized with different polymer componentsand ratios resulted in tau0 varying from 281 to 322 μs.

TABLE 9 Amount Particle 1 Polyethylene glycol methyl ether 250 μLmethacrylate (50% wt in water) DI Water 2.25 mL2,2-Dimethoxy-2-phenylacetonphenone 1.283 mg 2-(Diethylamino)ethylmethacrylate 135.5 μL Butyl methacrylate 21.5 μL tetra(ethylene glycol)dimethacrylate 38 μL Myristyltrimethylammonium bromide 2.86 mg Dodecyltetraethylene glycol ether 10 μL Pd-BP-AEME-4 (10 mM in DMSO) 32 μLParticle 2 Hydroxyethyl methacrylate 125 μL DI Water 2.375 mL2,2-Dimethoxy-2-phenylacetonphenone 1.283 mg Aminoethyl methacrylate135.5 μL Butyl methacrylate 21.5 μL tetra(ethylene glycol)dimethacrylate 38 μL Myristyltrimethylammonium bromide 2.86 mg Dodecyltetraethylene glycol ether 10 μL Pd-BP-AEME-4 (10 mM in DMSO) 32 μLParticle 3 Hydroxyethyl methacrylate 260.5 μL DI Water 2.375 mL2,2-Dimethoxy-2-phenylacetonphenone 1.283 mg Butyl methacrylate 21.5 μLtetra(ethylene glycol) dimethacrylate 38 μL Myristyltrimethylammoniumbromide 2.86 mg Dodecyl tetraethylene glycol ether 10 μL Pd-BP-AEME-4(10 mM in DMSO) 32 μL Particle Particle concentration Tau0 (μs) Particle1 25 (mg/100 μL) 280.9 Particle 2 25 (mg/100 μL) 321.5 Particle 3 12.5(mg/100 μL)   295.1

Reference is now made to FIG. 8, a flow diagram of method 800 ofdetecting one or more analytes. For example, the method 800 can beimplemented using the system 100 as shown and described with referenceto FIG. 5 and/or any of the sensors and/or dye-polymer formulationsdescribed herein to determine an analyte value (e.g., analyte quantityand/or concentration). For ease of description, method 800 is describedwith reference to system 100 as measuring a glucose and an O₂concentration using a multi-analyte sensor 110 having a first sensingportion that includes an O₂ sensitive luminescent sensing compound and asecond sensing portion that includes the same O₂ sensing compound andglucose oxidase.

At a step 810, optical detector 115 is placed on the skin in closeproximity to sensor 110. Then, sensor 110 is illuminated by pulsinglight source 120.

At a step 815, emission light 142 from first sensing portion and thesecond sensing portion of sensor 110 is captured via detector 125.Because first sensor portion and second sensor portion are composed ofdifferent polymer matrices, emission light 142 from sensor 110 includesa long-lifetime component and a short-lifetime component.

At a step 820, the optical signal captured by detector 125 is processedto determine a lifetime signal that is a mix of long-lifetime andshort-lifetime components. An example of a combined lifetime signal isshown in plot 400 of FIG. 6.

At a step 825, the lifetime signal determined in step 820 isdeconvoluted to derive the short-lifetime intensity and thelong-lifetime intensity. The short-lifetime signal corresponds to theoptical signal from second sensor portion (e.g., the glucose sensorportion) and the long-lifetime corresponds to the optical signal fromfirst sensor portion (e.g., the O₂ sensor portion). An example of adeconvoluted lifetime signal is shown in plot 400 of FIG. 6.

At a step 830, the short-lifetime intensity and the long-lifetimeintensity are correlated to analyte values (e.g., analyte quantityand/or concentrations).

Following long-standing patent law convention, the terms “a,” “an,” and“the” refer to “one or more” when used in this application, includingthe claims. Thus, for example, reference to “a subject” includes aplurality of subjects, unless the context clearly is to the contrary(e.g., a plurality of subjects), and so forth.

Throughout this specification and the claims, the terms “comprise,”“comprises,” and “comprising” are used in a non-exclusive sense, exceptwhere the context requires otherwise. Likewise, the term “include” andits grammatical variants are intended to be non-limiting, such thatrecitation of items in a list is not to the exclusion of other likeitems that can be substituted or added to the listed items.

For the purposes of this specification and appended claims, unlessotherwise indicated, all numbers expressing amounts, sizes, dimensions,proportions, shapes, formulations, parameters, percentages, quantities,characteristics, and other numerical values used in the specificationand claims, are to be understood as being modified in all instances bythe term “about” even though the term “about” may not expressly appearwith the value, amount or range. Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the followingspecification and attached claims are not and need not be exact, but maybe approximate and/or larger or smaller as desired, reflectingtolerances, conversion factors, rounding off, measurement error and thelike, and other factors known to those of skill in the art depending onthe desired properties sought to be obtained by the presently disclosedsubject matter. For example, the term “about,” when referring to a valuecan be meant to encompass variations of, in some embodiments, ±100% insome embodiments ±50%, in some embodiments ±20%, in some embodiments±10%, in some embodiments ±5%, in some embodiments ±1%, in someembodiments ±0.5%, and in some embodiments ±0.1% from the specifiedamount, as such variations are appropriate to perform the disclosedmethods or employ the disclosed compositions.

Further, the term “about” when used in connection with one or morenumbers or numerical ranges, should be understood to refer to all suchnumbers, including all numbers in a range and modifies that range byextending the boundaries above and below the numerical values set forth.The recitation of numerical ranges by endpoints includes all numbers,e.g., whole integers, including fractions thereof, subsumed within thatrange (for example, the recitation of 1 to 5 includes 1, 2, 3, 4, and 5,as well as fractions thereof, e.g., 1.5, 2.25, 3.75, 4.1, and the like)and any range within that range.

Although the foregoing subject matter has been described in some detailby way of illustration and example for purposes of clarity ofunderstanding, it will be understood by those skilled in the art thatcertain changes and modifications can be practiced within the scope ofthe appended claims. While various embodiments have been describedherein, it should be understood that they have been presented by way ofexample only, and not limitation. Furthermore, although variousembodiments have been described as having particular features and/orcombinations of components, other embodiments are possible having acombination of any features and/or components from any of embodimentswhere appropriate as well as additional features and/or components.

Where methods described herein indicate certain events occurring incertain order, the ordering of certain events may be modified.Additionally, certain of the events may be performed repeatedly,concurrently in a parallel process when possible, as well as performedsequentially as described above. Furthermore, certain embodiments mayomit one or more described events. Where methods are described, itshould be understood that such methods can be computer-implementedmethods. Similarly stated, a non-transitory processor readable mediumcan store code representing instructions configured to cause a processorto cause the described method to occur or be carried out.

Some embodiments described herein relate to computer-readable medium. Acomputer-readable medium (or processor-readable medium) isnon-transitory in the sense that it does not include transitorypropagating signals per se (e.g., a propagating electromagnetic wavecarrying information on a transmission medium such as space or a cable).The media and computer code (also can be referred to as code) may bethose designed and constructed for the specific purpose or purposes.Examples of non-transitory computer-readable media include, but are notlimited to: magnetic storage media such as hard disks, floppy disks, andmagnetic tape; optical storage media such as Compact Disc/Digital VideoDiscs (CD/DVDs), Compact Disc-Read Only Memories (CD-ROMs), andholographic devices; magneto-optical storage media such as opticaldisks; carrier wave signal processing modules; and hardware devices thatare specially configured to store and execute program code, such asASICs, PLDs, ROM and RAM devices.

Examples of computer code include, but are not limited to, micro-code ormicro-instructions, machine instructions, such as produced by acompiler, code used to produce a web service, and files containinghigher-level instructions that are executed by a computer using aninterpreter. For example, embodiments may be implemented using Java,C++, or other programming languages (e.g., object-oriented programminglanguages) and development tools. Additional examples of computer codeinclude, but are not limited to, control signals, encrypted code, andcompressed code.

What is claimed is:
 1. A sensor, comprising: a first polymer-luminescentsensing compound configured to produce a first luminescent signal in thepresence of a first analyte; and a second polymer-luminescent sensingcompound configured to produce a second luminescent signal in thepresence of a second analyte, the second luminescent signal having aluminescent lifetime that is at least 1.1 times greater than aluminescent lifetime of the first luminescent signal.
 2. The sensor ofclaim 1, wherein the first luminescent signal and the second luminescentsignal have a common spectral signature.
 3. The sensor of claim 1,wherein the second polymer-luminescent sensing compound has aluminescent lifetime that is at least 1.6 times greater than theluminescent lifetime of the first polymer-luminescent sensing compound.4. The sensor of claim 1, wherein the luminescent lifetime of the secondpolymer-luminescent sensing compound exceeds 350 microseconds.
 5. Thesensor of claim 1, wherein the second polymer-luminescent sensingcompound includes: Pd-BP-AEME-4, hydroxyethyl methacrylate, and ethyleneglycol dimethacrylate, a weight percentage of ethylene glycoldimethacrylate selected such that the second luminescent signal has theluminescent lifetime that is at least 1.1 times greater than aluminescent lifetime of the first luminescent signal.
 6. The sensor ofclaim 1, wherein the first analyte is oxygen and the second analyte isglucose.
 7. The sensor of claim 1, wherein: the firstpolymer-luminescent sensing compound includes an oxygen-sensitive dye;the second polymer-luminescent sensing compound includes theoxygen-sensitive dye; the first analyte is oxygen; and the secondanalyte is selected from the group consisting of glucose, lactate,alcohol, ascorbate, histamine, cholesterol, and pyruvate.
 8. The sensorof claim 7, wherein the second polymer-luminescent sensing compoundincludes an oxidase configured to cause oxygen to form H₂O₂ in thepresence of the second analyte such that the oxygen-sensitive dyeincluded in the second polymer-luminescent sensing compound produces thesecond luminescent signal based on a concentration of the secondanalyte.
 9. A sensor, comprising: a first polymer-luminescent sensingcompound configured to produce a first luminescent signal in thepresence of a first analyte; and a second polymer-luminescent sensingcompound configured to produce a second luminescent signal in thepresence of a second analyte, the second polymer-luminescent sensingcompound including a luminescent sensing compound and a polymer, polymerconfigured to alter a characteristic of the luminescent sensing compoundsuch that the second luminescent signal is distinguishable from thefirst luminescent signal.
 10. The sensor of claim 9, wherein the firstpolymer-luminescent sensing compound includes the luminescent sensingcompound.
 11. The sensor of claim 9, wherein the luminescent sensingcompound is a first luminescent sensing compound, the firstpolymer-luminescent sensing compound including a second luminescentsensing compound.
 12. The sensor of claim 9, wherein the second polymeris configured to increase an intensity of the luminescent sensingcompound such that the second luminescent signal has an intensity within25% of an intensity of the first luminescent signal.
 13. The sensor ofclaim 9, wherein the second polymer is configured to alter a lifetime ofthe luminescent sensing compound such that the second luminescent signalhas a lifetime at least 1.1 times a lifetime of the first luminescentsignal.
 14. The sensor of claim 13, wherein the firstpolymer-luminescent sensing compound includes the luminescent sensingcompound.
 15. The sensor of claim 9, wherein the luminescent sensingcompound and the polymer are chemically bound to form the secondpolymer-luminescent sensing compound.
 16. The sensor of claim 9, whereinthe luminescent sensing compound is physically bound to the polymer toform the second polymer-luminescent sensing compound.
 17. A method,comprising: illuminating a sensor having a first polymer-luminescentsensing compound and a second polymer luminescent sensing compound withan excitation light; receiving, from the sensor, a luminescent signalincluding a component from the first polymer-luminescent sensingcompound and a component from the second polymer luminescent sensingcompound; deconvoluting the component from the first polymer-luminescentsensing compound and the component from the second polymer luminescentsensing compound based on the first polymer-luminescent sensing compoundhaving a luminescent lifetime greater than a luminescent lifetime of thesecond polymer-luminescent sensing compound; determining a concentrationof the first analyte based on the component of the emission spectrumassociated with first polymer-luminescent sensing compound; anddetermining a concentration of the second analyte based on the componentof the emission spectrum associated with second polymer-luminescentsensing compound.
 18. The method of claim 17, wherein the component fromthe first polymer-luminescent sensing compound and the component fromthe second polymer luminescent sensing compound have the same emissionspectrum.
 19. The method of claim 17, wherein the firstpolymer-luminescent sensing compound has a luminescent lifetime at least1.1 times greater than a luminescent lifetime of the secondpolymer-luminescent sensing compound.